Going by the specs on the respected sites of the subs the BTL can handle 2000W RMS, the HDC3 can handle 1000w RMS so two audioques are going to take as much power as a single BTL (according to specs). Also the BTL has a slightly higher sensitivity so in that regard it would be louder with equal power. Really though I don't see a bad choice, each setup has cons and pros but they will both be loud in the correct box.